1. Field of the Invention
The present invention relates generally to an image capturing device with an automatic focus function, a method and program for controlling an image capturing device with an automatic focusing function.
2. Description of the Related Art
Conventionally, in an automatic focusing (AF) process of digital cameras, a technique of setting a plurality of AF areas in an image capture frame (Jpn. Pat. Appln. KOKAI Publication No. 2007-178576, for example), and a technique of tracking a subject and automatically focusing the subject (Jpn. Pat. Appln. KOKAI Publication No. 2006-184742, for example) have been known.
In the technique disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2007-178576, however, AF areas are set in predetermined positions in an image capture frame, and the AF areas are set irrelevant of the shape of a specific subject to be automatically focused. Further, the technique of Jpn. Pat. Appln. KOKAI Publication No. 2007-178576 does not set a plurality of AF areas with respect to one subject to be automatically focused. Accordingly, when the contrast of a subject to be automatically focused varies from region to region, an AF area may be set in a low-contrast region, which generates a problem of deterioration in AF precision. Further, even by applying the technique disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2006-184742, it is impossible to prevent an AF area from being set in a low-contrast portion.
When a large AF area is set so as to include the overall subject, the contrast gradient in the AF process may be reduced, which generates a problem of deterioration in precision of detecting a peak contrast.